Software

On power supplies and capacitors

Got a PM on reddit recently about listing PSU tiers and PSUs with 30C rated components.

I've seen comments that some power supplies only have capacitors rated for 30C. Stop. Please stop. It's like a bad rumor that's taken on legs and the story gets more outlandish the longer it goes on. Next thing you know we'll have people saying that if the room exceeds 30C your PSU will take out all the components in your build. Oh wait, that's already happened.

If we're going to talk about specs on a PSU, show proof and talk technical details. Cite reliable sources. If you're going to say it isn't designed for gaming builds, show proof. (Marketing blurbs saying a PSU is designed for price-conscious users does not prove it can't power a gaming build.) Real and reliable bench tests don't lie.

As for my background, I studied and competed in electronics servicing. Even won at the national level. I loved it - I studied college EE textbooks in high school, studied EE in college until switching to computer engineering (effectively a CS major with EE minor). Electrical engineering has always been my first technical love, and it's a domain I continue to try and grow in. I've built plenty of circuits from class A amplifiers to custom PC expansion cards to (non-switching) power supplies, etc. Designed and built plenty of other circuits, and fixed many more.

Plenty of people talk about capacitors like it's some linear component - like if the capacitance value is double it's twice as good. But it doesn't always work that way. The values are chosen and tuned, and what size they need to be, what voltage they need to be, and what tolerance rating they need to have depends on how it's used and what kind of circuit it's in. Sometimes you need narrow tolerance caps. Other times, having one that is rated for -20/+85% (like a lot of electrolytics) is perfectly fine and the circuit is designed to handle that variation and remain in spec. That's the EEs job. There is not just capacitance, but also have leakage currents, inherent resistance, temperature coefficients, etc. It's not as simple as brand X vs Y. But people without the background don't know this, and assume that cap X vs cap Y is so much better, or that cap Z is bad, etc.

So when it comes to claims about components, particularly power supplies and voltage regulation, my bar for what constitutes valid evaluation and feedback is considerably higher. My tolerance for bogus facts and erroneous claims is extremely low. If you see posts on review sites talking about capacitor "performance", consider it with a high degree of skepticism. No EE that I know of talks about caps in some absolute term of "performance". There's rated specs and adherence to that, but not some linear scale "performance".

I guess corsair does this to justify a 100,000 hour MTBF. So in conclusion it won't last that long. The RMi which is an excellent unit has the same 100,000 hour MTBF but rated at 50C.

So when it comes to claims about components, particularly power supplies and voltage regulation, my bar for what constitutes valid evaluation and feedback is considerably higher.

it would be great if you are able to get the proper equipment and start making reviews. :) We need more reviewers like jonyguru that are not biased!! It just hurts me to see people that once said something and now say the contrary because of convenience (this is very misleading to many people).

example: I'm sure the corsair CX series would work fine even at 40C. But if you check under tech specs

Right right! I don't dispute that number at all. Part of why I posted the topic is that I've literally seen this progression on these forums:

Corsair publishes spec of 30C continuous output

Then the bad claims start... Another person reads that and posts that they only uses capacitors rated for 30C... (sigh)

Next person comes along and posts that if you go over 30C, that capacitor is going to blow and take out all your parts

Next person comes in and posts that all of that series are ticking time bombs

(edit, because I literally just saw this today) Next person says don't ever buy from said manufacturer.

And then on and on it goes, until it become a meme or groupthink. That's what I'd love to see die off. Lets evaluate units on their technical merits, not subjective tiers. I'm a big fan of JonnyGuru and how they review PSUs. Perhaps one day we'll start reviewing PSUs in a similar manner, who knows. :)

Unfortunately many people link Jonnyguru with Corsair and automatically make the assumption that he is biased towards Corsair, even though Jonny Guru himself doesn't even do reviews anymore. The site is unbiased. Period.

Not really true. That site fails to mention if they were sent the unit or if they bought it for many of their PSU reviews. It is a common practice with all computer components.

This is why we get decent cx750 reviews (even though anyone who knows OklahomaWolf knows that the cx750 review is cleverly worded and he knows it is not good), and much worse reviews. HardOCP for example BOUGHT their CX750, not had it delivered from Corsair directly.

So let's evaluate on data, not on "clever words". Measurements properly done on representative samples don't lie, and then it doesn't matter what editorial content there is surrounding it. No "do you work for them?" conspiracies or whatnot.

OklahomaWolf's review and HardOCP reviews show the same results. No evidence of a better unit in one over the other. The difference is how they write their reviews on PSUs across the board. HardOCP will put the hard "Pass" or "Fail" on a unit and will be very critical of any unit that fails. JonnyGuru's site has always written reviews that don't call units bad, or even poor if they will not harm you components or burn your house down.

This is all REALLY great info and it is great for people to read, but I really hope it doesn't make people think that any PSU with the right wattage/amperage for their build will be fine.

I do agree with only using concrete evidence to back up claims. Like if you don;t recommend the CX750, post the HardOCP review of it. Simple. Too many people run around saying things with no evidence.

There are also a REALLY big number of people who disregard common sense. For example people will say that a 500w PSU with 20a on the 12v rail and a continuous rating of 380w(MAX of 500w) is fine for a middle of the road gaming PC because no one can post a review of the unit simply because it is so awful that no company has wasted time/money to review it. I have seen this many times here.

Couldn't have been said any better. 'Bout time someone did haha. Iv'e used the CX series a couple times in personal rigs and never had an issue. Every manufacturing corp. has its flaws, but to stack all the "Bad/Crap" title on this particular series is just not logical. Thanks for sharing that tiny :>

Thank you Philip for posting this. No more "cx sux, it's tier 42 & has bad capacitors!!1!!" That's pretty cool how you did electrical engineering! Also, which PSU review sites do you reccomend? I personally trust jonnyguru, are there any others that are good?

People should still understand that some PSUs are not great for their situation. This article will help them do so. If anything this will help people to understand that some of those units (CX,TR2,etc.)really are not OK for their system.

I'm a bit late here, but TechPowerUp and HardOCP are both pretty in depth. HardOCP is really critical, so if something passes with a gold or silver rating you know it's a good power supply.

These aren't dedicated PSU review sites but they're still a couple of my favorite for looking at PSU reviews. Hardwaresecrets also reviews a lot of cheaper power supplies among the more expensive ones.